Organoids and Boltzmann Brains
These clumps of grey matter spontaneously organize themselves into something like mini-brains, developing axons and dendrites, developing neural connections, and sending each other electrical neural signals. These organoids clearly have the potential to teach a lot about brain development, brain function, and brain disease.
They also pose deep ethical questions. Nobody thinks that these organoids are conscious - yet - but the potential is there. Experimenters are already plotting to make them more brain like by providing them with blood supplies and sensory inputs.
Quanta takes a look at the nascent ethical concerns: https://www.quantamagazine.org/an-ethical-future-for-brain-organoids-takes-shape-20200123/
Human ability to play god is getting serious.